SeaWorld executive Dan Decker has been replaced after a significant drop in attendance and several animal deaths at the San Antonio, Texas, park location. On Friday, SeaWorld Inc. announced a shakeup in several executive teams that affects five of its 11 theme parks.

Carl Lum, president of Busch Gardens Williamsburg and Water Country USA, will be Decker’s replacement as SeaWorld San Antonio park director, according to a report from the Houston Chronicle. In addition to being in charge of park operations, he will also be tasked with running another Texas park, Aquatica. Lum has been with the company for over 16 years and has held various other positions, including vice president of finance for Busch Gardens in Tampa, Florida.

According to a company press release, Decker is immediately departing with the company after 12 years leading the San Antonio park. SeaWorld executives have not commented or elaborated on his quick exit.

With ticket sales dropping and controversy over several animal deaths, SeaWorld Inc. has made several changes to its executive teams. [Photo by Gerardo Mora/Getty Images]SeaWorld executive Daniel Brown is retiring from the chief parks operation officer position and will be replaced by San Diego, California park president John Reilly. The current vice president of global sales for SeaWorld, Marilyn Hannes, will be taking over Reilly’s former position.

Another SeaWorld executive Dr. Christopher Dold will be promoted to chief zoological officer from his current position as vice president of veterinary services. He replaces Brad Andrews, who will continue in an advisory position.

“These leaders bring to their new roles an extraordinary depth of knowledge and talent and the right expertise to deliver on our strategic priorities,” SeaWorld CEO Joel Manby said in a statement.

The shakeup of SeaWorld executives is part of an overall plan to overhaul the company and boost attendance at its San Antonio and San Diego parks. Last fall, Manby announced a strategy to clean up SeaWorld’s image by promoting its animal rescue efforts, as well as adding new attractions and resorts to the parks.

SeaWorld has been under tremendous public pressure since a 2013 documentary questioned the company’s treatment of animals involved in shows, particularly the interactions between trainers and orcas. The film, titled Blackfish, was based on the 2010 death of trainer Dawn Bracheau, who was killed by an orca named Tilikum at SeaWorld Orlando.

Former SeaWorld CEO Jim Atchison resigned in late 2014 amid strong criticism and negative publicity after the documentary’s release.

In response to visitor feedback, Manby announced changes to the killer whale show at the San Diego park. The new show will have a conservation theme and the orcas will be placed in “natural settings,” according to a company statement last year. The shows at the San Antonio and Orlando parks will remain unchanged.

A new killer whale show is set to start at SeaWorld San Diego later this year. [Photo by SeaWorld via Getty Images]Since last summer, four animal deaths have been reported at the SeaWorld San Antonio park, including a 12-year-old Pacific white-sided dolphin earlier this month. A killer whale named Unna died in December from a bacterial infection and Stella, a 2-year-old beluga whale, died after being treated for gastrointestinal problems in November. In July, a baby beluga died shortly after being born.

“It has been a difficult time for our San Antonio team, with several other recent deaths,” SeaWorld said in February 6 blog post the day after the dolphin’s death. “While there are no apparent connections between these deaths, our veterinarians will be conducting a thorough review of all the cases as they work through the postmortem examination process.”

As of January, SeaWorld Orlando does not allow visitors to swim next to beluga whales. However, San Antonio and San Diego will continue to offer the experience.

Meanwhile, the San Diego park will be opening a new environment for bottlenose dolphins dubbed Discovery Point later on this year. The new habitat will be twice the size of the park’s current one and guests will have the opportunity to swim with the dolphins for 30 minutes.

SeaWorld has 11 parks in five states, including Busch Gardens and Aquatica. Through the first nine months of 2015, company revenue was down one percent to $1.1 billion and net income dropped 20 percent to $60.2 million.

The shakeup of SeaWorld executives will be complete as of April 1. The company has not commented specifically about the reasoning behind the changes or the departure of Dan Decker as it does not discuss personnel matters publicly.